1. Field of the Invention
The present invention is related to a roll winder including a roll retainer, which is coupled to a wound roll in the region of its pivot axis, to a support apparatus, and to a process.
2. Discussion of Background Information
Beyond certain roll diameters, roll winders, which are provided to hold a roll in a region of its pivot axis, require that the wound roll be supported from below. Otherwise, under the influence of its own weight, the wound roll would sag too much, which can lead to damage to the web of material.
However, supporting the wound roll from below leads to the problem that the bearing pressure has an influence on the winding hardness. In particular, for take-up winding, the influence of bearing pressure on the winding hardness can lead to undesired results. In principle, it is desirable to have the winding hardness decrease from the inside out. However, with increasing bearing pressure, winding hardness increases from the inside out, i.e., contrary to the desired effect.
Some suggestions have already been made in the prior art for addressing this problem. For example, one proposal is based on supporting the wound roll on an air cushion. However, this is relatively energy-intensive. Another solution is to arrange the wound roll on a revolving belt that is tensed between two deflection rolls, which sometimes causes considerable wear.